Arsenic, drinking-water and health risk substitution in arsenic mitigation: A discussion paper
Ongoing surveillance and support
The development of ongoing surveillance should be an essential component of the mitigation programme. Pilot activities in developing surveillance of water supplies have been undertaken in urban areas of Bangladesh (for example Rajshahi and Mymensingh) by DPHE with support from WHO and DFID via a WEDC research project. and in Rajhahi and Mymensingh from DFID (via WEDC). Work has also been undertaken on development surveillance activities for small towns.
Surveillance in urban areas has involved testing of both piped and non-piped water sources for microbial and chemical quality, sanitary inspections of facilities and testing of household water. The use of surveillance information has been used in developing improvements undertaken by City Corporations and by communities to improve water quality and sanitary conditions. Both laboratory methods and field kits have been used to undertake these activities. In addition, there has been development of widespread testing of water quality, particularly testing for arsenic, in rural areas. A protocol for the development of a rural water quality surveillance programme has been prepared for DPHE, which includes recommended parameters for inclusion, frequency of testing for different technologies and household water, and provides an institutional framework for surveillance implementation.
There is a need to develop and roll-out surveillance programmes as part of the mitigation programme. This will help to ensure that operation and maintenance of technologies introduced during the emergency response is effective. It will also provide opportunities to support hygiene education and to use water quality testing and as an entry for point for improving overall water safety. The implementation of a surveillance programme will also greatly strengthen the evaluation of the impact of the emergency response and in refining policy and strategy for arsenic mitigation.
The surveillance programme should include testing of microbial quality using in the first instance E.coli or thermotolerant coliforms, but increasing aiming to introduce other index organisms. Sanitary inspections should also be undertaken. It should also include testing of arsenic in tuebwells, both those previously identified as being contaminated and those previously identified as being arsenic safe. Other parameters as per the protcol for surveillance should also be included. Ongoing collection of this data is important in order to assess whether temporal changes occur in arsenic concentrations.
Surveillance programmes in rural areas should not attempt to visit and test every water supply on a regular basis. A rolling program of visits to water supplies should be developed with an aim to visit each supply once every 3-5 years and either stratified random sampling or cluster sampling used to select specific supplies to be visited.